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<title>Using as: H8/300-Regs</title>

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Next: <a href="H8_002f300_002dAddressing.html#H8_002f300_002dAddressing" accesskey="n" rel="next">H8/300-Addressing</a>, Previous: <a href="H8_002f300_002dChars.html#H8_002f300_002dChars" accesskey="p" rel="prev">H8/300-Chars</a>, Up: <a href="H8_002f300-Syntax.html#H8_002f300-Syntax" accesskey="u" rel="up">H8/300 Syntax</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="AS-Index.html#AS-Index" title="Index" rel="index">Index</a>]</p>
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<a name="Register-Names-7"></a>
<h4 class="subsubsection">9.12.2.2 Register Names</h4>

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<p>You can use predefined symbols of the form &lsquo;<samp>r<var>n</var>h</samp>&rsquo; and
&lsquo;<samp>r<var>n</var>l</samp>&rsquo; to refer to the H8/300 registers as sixteen 8-bit
general-purpose registers.  <var>n</var> is a digit from &lsquo;<samp>0</samp>&rsquo; to
&lsquo;<samp>7</samp>&rsquo;); for instance, both &lsquo;<samp>r0h</samp>&rsquo; and &lsquo;<samp>r7l</samp>&rsquo; are valid
register names.
</p>
<p>You can also use the eight predefined symbols &lsquo;<samp>r<var>n</var></samp>&rsquo; to refer
to the H8/300 registers as 16-bit registers (you must use this form for
addressing).
</p>
<p>On the H8/300H, you can also use the eight predefined symbols
&lsquo;<samp>er<var>n</var></samp>&rsquo; (&lsquo;<samp>er0</samp>&rsquo; &hellip; &lsquo;<samp>er7</samp>&rsquo;) to refer to the 32-bit
general purpose registers.
</p>
<p>The two control registers are called <code>pc</code> (program counter; a
16-bit register, except on the H8/300H where it is 24 bits) and
<code>ccr</code> (condition code register; an 8-bit register).  <code>r7</code> is
used as the stack pointer, and can also be called <code>sp</code>.
</p>



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